Event-related oscillations in offspring of alcoholics: neurocognitive disinhibition as a risk for alcoholism

Abstract

Background: Event-related oscillations (EROs) are increasingly being used to assess neurocognitive functioning in normal and clinical populations. The current study compares different frequency activities in offspring of alcoholics (OA) and in normal control subjects (NC) to examine whether the OA group exhibits any abnormality in oscillatory activity while performing a Go/NoGo task.

Methods: The S-transform algorithm was employed to decompose the electroencephalographic (EEG) signals into different time-frequency bands, and the oscillatory responses in the P300 time window (300-700 milliseconds) were statistically analyzed in both groups.

Results: The OA group manifested significantly decreased activity in delta (1-3 Hz), theta (4-7 Hz), and alpha1 (8-9 Hz) bands during the NoGo condition, as well as reduced delta and theta activity during the Go condition. This reduction was more prominent in the NoGo than in the Go condition.

Conclusions: The decreased response in delta, theta, and alpha1 oscillations, especially during the NoGo condition in high-risk individuals, is perhaps suggestive of cognitive and neural disinhibition and may serve as an endophenotypic marker in the development of alcoholism and/or other disinhibitory disorders.

Figure 1

The ERPs and time-frequency representation of Go and NoGo condition for the NC and OA groups at CZ electrode. Note the lower P3 amplitude and decreased energy in low frequency activity in both Go and NoGo conditions in the OA compared to the NC group. The time window of 300–700 ms is marked with dotted white line in the time-frequency plots. The color scale represents the decomposed energy for both groups.

Figure 2

The energy curves showing the comparison of NC and OA groups in Go and NoGo condition. These curves were obtained from the amplitude envelope of a particular spectral activity derived from S-Transform.

Figure 3

The bar graphs showing mean amplitude values (300–700 ms) between NC (green line) and OA (red line) groups in Go and NoGo condition. As seen, the group difference in NoGo activity is more robust in delta (A), theta (B), and alpha1 (C) activity at frontal (F), central (C), and parietal (P) regions. (The error bars represent standard error).

Figure 4

The topographic mapping of the mean NoGo activity (in μV) at delta, theta, and alpha1 bands in NC and OA groups. The activity represents the average of all the amplitude values between 300–700 ms post-stimulus. The OA group shows lower activity in delta and theta bands, while showing a weaker anterior-posterior communication in alpha1 band.